Ben ate 3 slices of cake. Luis ate 2 slices. If Ben ate $\dfrac{3}{8}$ of the cake, what fraction of the cake was eaten?
Explanation: If 3 slices represent $\dfrac{3}{8}$ of the cake, there must have been a total of 8 slices. $\text{fraction of cake eaten} = \dfrac{\text{number of slices eaten}}{\text{number of slices total}}$ They ate ${5}$ out of $8$ slices. They ate $\dfrac{5}{8}$ of the cake.